It's impossible to stay at peak motivation all the time; the intensity of it would leave us emotionally and physically exhausted. Although perhaps I should re-phrase that because there are some people - many people, in fact - who operate constantly at a very high rate of intensity. I'm sure they do crash and recover, and find their own coping strategies (just take a look at the film Phantom Thread for an example of this).
At the moment, I'm in a 'low' phase, and finding it difficult to motivate myself, finding it difficult to do the things that need to be done. It seems much easier and by far nicer, to just not do anything much. I know that this is a byproduct of having just completed probably one of the most intense four-month periods of my professional life. However, it's frustrating to be in a state where tasks that should take ten minutes are taking an hour, simply because I'm lacking the impetus to execute mentally.
Now, this is nothing more than a mental problem, pure and simple, and it's ever so slightly fascinating, too. I know that there is nothing stopping me from doing X or Y except a little voice somewhere (somewhere) in my brain. It's not active, nor is it foreboding. It's a much more subtle force saying something along the lines of, 'You really shouldn't be bothered to do this. This is really boring.' Why? Why shouldn't I be bothered, and where does this voice come from? Should I listen to it, or try to quieten it? (I should say, just for the record, I'm not actually hearing voices, or a voice, but there is something there motivating my (in)actions).
I think the best thing to do when in these types of ruts take hold is to do what one can. So, if it takes an hour to do something that at peak motivation would take ten minutes, so be it. Yes, it's frustrating, but letting myself slide into, potentially, a cauldron of inactivity doesn't seem the way to go, either. I have, therefore, talked myself into trying to be happy with doing less (much less) and taking things slowly, patting myself on the back that I'm able to get anything done at all, safe in the knowledge that it's a temporary state of being only.